refactor(cli): separate binary entry points from library logic

Move the main execution logic to a dedicated internal module and create distinct entry files for each binary to improve project structure and build configuration.

crates/irtt-cli/src/lib.rs

@@ -2,5 +2,7 @@
 
 pub mod applet;
 pub mod cmd;
+#[doc(hidden)]
+pub mod entry;
 pub mod shared;
 pub mod signal;